Patent application title: POLYMERIC NANOCAPSULES FOR USE IN DRUG DELIVERY

Abstract:

The present invention relates to drug delivery formulations that utilize
nanocapsules, such as nanovesicles, micelles, lamellae particles,
polymersomes, dendrimers, and other nano-size particles of various other
fabrications, including those that are known in the art. The invention
employs diblock copolymers or single block polymers that hold, adhere to,
absorb or encapsulate drug molecules, including, but not limited to,
those that heretofore have not been successfully formulated for oral drug
delivery, e.g., insulin. Nanocapsule holding, adherence, absorption or
encapsulation of such drugs or other molecules enables their delivery via
oral or mucosal means.

Claims:

1. A composition comprising:a diblock copolymer comprising polymer blocks
A and B, whereinA is at least a partially hydrophobic block andB is at
least a partially hydrophilic block, andwherein A and B further comprise
amino acids or derivatives of amino acids.

2. A composition according to claim 1 wherein block A comprises an
n-butyl-poly-l-lactide polymer or a derivative thereof.

3. A composition according to claim 1 wherein block B comprises a
poly-l-glutamic acid polymer or a derivative thereof.

4. A composition according to claim 1 wherein the diblock polymer
comprises poly(lactic acid)-poly(glutamic acid) or a derivative thereof.

5. A composition according to claim 1 wherein the A block comprises a
polylactide, polycaprolactide, or polyglycolide, or derivatives thereof,
including such entities in either enantiomeric, racemic or other isomeric
forms such as meso.

6. A composition according to claim 1 wherein the B block comprises
polyaminoacids, or derivatives thereof, with ionic nature, including
polyaminoacids in enantiomeric, racemic, or other isomeric forms such as
meso.

7. A composition according to claim 1 wherein the B block comprises
polyaminoacids, or derivatives thereof, with anionic nature, including
polyaminoacids in enantiomeric, racemic, or other isomeric forms such as
meso.

8. A composition according to claim 1 wherein the B block comprises
polyaminoacids, or derivatives thereof, with cationic nature.

9. A composition according to claim 1 wherein the B block comprises
polyglutamic or polyaspartic amino acids, or derivatives thereof, or
copolymers of the two.

10. A composition according to claim 1 wherein the B block comprises
polylysine, polyarginine, polyhistidine, or derivatives thereof, or any
combinations of copolymers thereof.

11. A composition according to claim 1 wherein said diblock polymer forms
nanocapsules.

12. A composition according to claim 11 wherein the nanocapsules comprise
nanoparticles.

13. A composition according to claim 11 wherein the nanocapsules comprise
micelles.

14. A composition according to claim 11 wherein the nanocapsules are
lamella shaped.

15. A composition according to claim 11 wherein the nanocapsules comprise
both micelles and lamellae shaped particles.

16. A composition according to claim 11 wherein the nanocapsules comprise
polymersomes.

17. A composition according to claim 11 wherein the nanocapsules comprise
nanovesicles.

18. A composition according to claim 11 wherein the nanocapsules comprise
dendrimers.

19. A composition according to claim 11 wherein a drug is adhered to, or
present on or in, all or part of the nanocapsules.

20. A composition according to claim 11 wherein a drug is at least
partially absorbed, or encapsulated by, all or part of the nanocapsules.

21. A composition according to claim 19 wherein the drug is a peptide,
polypeptide or protein.

22. A composition according to claim 19 wherein the drug is a
macromolecule.

23. A composition according to claim 19 wherein the drug is insulin.

24. A composition according to claim 19 wherein the drug is a derivative
or analogue of insulin.

25. A composition according to claim 20 wherein the drug is a peptide,
polypeptide or protein.

26. A composition according to claim 20 wherein the drug is a
macromolecule.

27. A composition according to claim 20 wherein the drug is insulin.

28. A composition according to claim 20 wherein the drug is a derivative
or analogue of insulin.

29. A composition according to claim 1 wherein either or both of blocks A
and B may vary in length between approximately 10 and 500 monomeric
units.

30. A composition according to claim 1 wherein either or both of blocks A
and B may vary in length between approximately 25 and 200 monomeric
units.

31. A composition according to claim 1 wherein either or both of blocks A
and B may vary in length between approximately 50 and 150 units.

32. A composition according to claim 1 except wherein the composition
comprises only the B block comprising a polyamino acid, or a derivative
thereof, capable of complexing with a drug such that the B block protects
the drug before being uptaken by the intestine.

33. A composition according to claim 1 except wherein the composition
comprises the B block but not the A block.

34. A composition according to claim 6 except wherein the composition
comprises the B block but not the A block.

35. A composition according to claim 7 except wherein the composition
comprises the B block but not the A block.

36. A composition according to claim 8 except wherein the composition
comprises the B block but not the A block.

37. A composition according to claim 9 except wherein the composition
comprises the B block but not the A block.

38. A composition according to claim 10 except wherein the composition
comprises the B block but not the A block.

41. A nanocapsule according to claim 40 wherein the nanocapsule comprises
a nanoparticle.

42. A nanocapsule according to claim 40 wherein the nanocapsule comprises
a micelle.

43. A nanocapsule according to claim 40 wherein the nanocapsule comprises
a lamella shaped structure.

44. A nanocapsule according to claim 40 wherein the nanocapsule comprises
a polymersome.

45. A nanocapsule according to claim 40 wherein the nanocapsule comprises
a nanovesicle.

46. A nanocapsule according to claim 40 wherein the nanocapsule comprises
a dendrimer.

47. A method of making an amino acid or amino acid derivative diblock
copolymer that forms nanocapsules, comprising:polymerizing two individual
amino acid or amino acid derivative polymeric blocks;coupling the two
blocks together to form a diblock polymer;precipitating the diblock
polymer after the coupling;washing the precipitated diblock
polymer;forming a diblock polymer suspension;sonicating the diblock
polymer suspension, andforming nanocapsules in the suspension.

48. A method according to claim 47 wherein a drug is added to the
nanocapsules.

49. A method according to claim 48 wherein the drug is a peptide,
polypeptide or protein.

50. A method according to claim 48 wherein the drug is insulin.

51. A method according to claim 48 wherein the drug is an insulin
derivative or analogue.

52. A method of treating a patient in need of insulin comprising
administering to said patient a pharmaceutically acceptable amount of a
composition of claim 23.

53. A method of treating a patient in need of insulin comprising
administering to said patient a pharmaceutically acceptable amount of a
composition of claim 24.

54. A method of treating a patient in need of insulin comprising
administering to said patient a pharmaceutically acceptable amount of a
composition of claim 27.

55. A method of treating a patient in need of insulin comprising
administering to said patient a pharmaceutically acceptable amount of a
composition of claim 28.

Description:

BACKGROUND OF THE INVENTION

[0001]1. Field of the Invention

[0002]Generally speaking, the pertinent field of the present invention
relates to drug delivery formulations that form nanoparticles which
absorb drugs and deliver them to the body. Such drugs include, for
example, peptides and proteins, which are delivered by nanoparticles to
the gastrointestinal tract and other portions of the body. More
particularly, the technology relating to the general aspect of the
invention employs copolymers that form nanocapsules in aqueous solution.
These formulations enable the oral and mucosal delivery of polypeptides
and macromolecules, e.g., insulin and other polypeptides, that heretofore
have not been successfully formulated for oral and mucosal drug delivery.

[0003]2. Description of the Related Art

[0004]The use of polymers in drug formulations is known. See, for example,
U.S. patent publication 2005196343 A1 (Sep. 8, 2005) to Reddy et al.
which is said to relate to polymeric nanoparticles, particularly useful
in drug and agent delivery; WO 2005079861 A2 (Sep. 1, 2005) to Lee, which
is said to relate to a conjugate comprising a chemotherapeutic agent
(such as an antitumor drug) conjugated to a water soluble polyamino acid
polymer; WO 2005056641 A1 (Jun. 23, 2005) to Kataoka et al. which is said
to disclose a coordination complex of a block copolymer comprising a
poly(ethylene glycol) segment and a poly(carboxylic acid) segment with
diaminocyclohexaneplatinum(II); WO 2005051416 A1 (May 27, 2005) to
Pouliquen et al. which is said to disclose pharmaceutical formulations
containing stable aqueous colloidal suspensions for the prolonged release
of an active ingredient, particularly a protein; KR 2003018549 A (Mar. 6,
2003) to Byun et al. which is said to disclose a phospholipid liposome
containing the combination of a negatively charged polymer and a
phospholipid; U.S. patent publication 2004136961 A1 (Jul. 15, 2004) to
Prokop et al. which is said to disclose compounds comprising a
water-based core solution and a water-based corona solution surrounding
the core solution; U.S. patent publication 2004052865 A1 (Mar. 18, 2004)
to Gower et al. which is said to pertain to core shell particles having a
core encapsulated within a calcium carbonate shell with an intermediate
layer composed of an amphiphilic compound; WO 2003101476 A1 (Dec. 11,
2003) to Piccariello et al. which is said to relate to active agent
delivery systems and specifically compounds that comprise amino acids
covalently attached to active agents; JP 2003327693 A2 (Nov. 19, 2003) to
Akashi et al. which is said to disclose poly(γ-glutamic acid)(I)
derivatives useful for drug carriers; U.S. patent publication 2003194438
A1 (Oct. 16, 2003) to Prescott et al. which is said to disclose an
extended-release analgesic for controlling pain comprised of an opioid or
non-opioid analgesic drug ionically bound to hyaluronic acid,
polyglutamic acid or other ionic polymers; WO 2003079972 A2 (Oct. 2,
2003) to Piccariello et al. which is said to relate to active agent
delivery systems, specifically to compounds that comprise amino acids, as
single amino acids or peptides, covalently attached to active agents; WO
2003055935 A1 (Jul. 10, 2003) to Li et al. which is said to concern a
design for dendritic poly(amino acid) polymer carriers having multiple
functional groups at the polymer surface and heterofunctional groups on
the poly(amino acid) side chains for drug or diagnostic agent attachment;
U.S. patent publication 2003054977 A1 (Mar. 20, 2003) to Kumar et al.
which is said to disclose a specified process for preparing a conjugate
of poly(glutamic acid) and a therapeutic agent; WO 2003011226 A2 (Feb.
13, 2003) to Ignatious which is said to disclose conjugates of a polymer
and biomimetic antagonist to a receptor upregulated at a disease site; WO
2002087497 A2 (Nov. 7, 2002) to Li et al. which is said to disclose
conjugate molecules comprising a ligand or a targeting moiety bonded to a
polymer spacer, a polymer carrier bonded to the polymer spacer, and a
therapeutic agent bound to the polymer carrier (with or without a
linker); U.S. patent publication 2002128177 A1 (Sep. 12, 2002) to Latham,
which is said to disclose a method of protecting a chemical compound from
degradation comprising combining the chemical compound with an amino acid
polymer; U.S. patent publication 2002099013 A1 (Jul. 25, 2002) to
Piccariello et al., which is said to claim compounds comprising a
polypeptide and an active agent covalently attached to the polypeptide
and a method for delivery of an active agent to a patient by
administering the compound to a patient; WO 2002026241 A1 (Apr. 4, 2002)
to Kataoka et al., which is said to disclose a complex comprising
cisplatin and a poly(ethylene glycol)/poly(glutamic acid) block
copolymer, wherein the cisplatin is enclosed in the copolymer through
ligand displacement in which a carboxyl anion of the copolymer is
replaced with a chlorine ion of the cisplatin; WO 2001089477 A2 (Nov. 29,
2001) to Mcginniss et al., which is said to disclose compounds and
methods for controllably releasing a material or active ingredient from a
polymer matrix; WO 2001047501 A1 (Jul. 5, 2001) to Prokop in which it is
said that microparticles and nanoparticles prepared from oppositely
charged polymers are provided in which a drug is incorporated into the
core and is conjugated to one polymer by a Schiff-base crosslink; WO
9918934 A1 (Apr. 22, 1999) to Prokop, which is said to disclose a method
of making particles useful in drug delivery, comprising the steps of:
contacting polyanionic polymers with cations in a stirred reactor so that
polyanions and the cations react to form particles; WO 9851284 A1 (Nov.
19, 1998) to Unger, which is said to be directed to targeted therapeutic
delivery systems comprising a gas or gaseous precursor filled microsphere
wherein said gas or gaseous precursor filled microsphere comprises an
oil, a surfactant, and a therapeutic compound, and WO 9851282 A1 (Nov.
19, 1998) to Unger, which is said to disclose a solid porous matrix
formed from a surfactant, a solvent, and a bioactive agent.

[0005]In the field of drug delivery, attempts have been made to create
systems and materials that successfully deliver insulin to the body by
the oral route with a reduced degradation of the insulin by
gastrointestinal enzymes. A report by Ghilsai, Drug Delivery Systems,
BUSINESS BRIEFING: PHARMAGENERICS (2003), describes a number of
approaches to achieving oral delivery of insulin, but states that in most
of the approaches described therein, only a small amount of insulin is
absorbed in oral administration. Kidron et al. in an abstract, A Novel
Peroral Insulin Formulation: Proof of Concept Study in Non-diabetic
Subjects, Diabet. Med. 21, 354-357 (2004) reports the oral administration
to subjects of an insulin containing delivery agent comprising (sodium
N-[8-(2-hydroxybenzoyl)amino]caprylate) ("SNAC"), and purports to
disclose that insulin was absorbed through the gastrointestinal tract in
a bioactive form. Gowthamarajan et al., Oral Insulin--Fact or Fiction,
RESONANCE, May 2003 reports that the strategy of utilizing insulin loaded
with nano/microcapsules has been tested a number of times, but that the
uptake of insulin via oral route, despite all the precautions, was less
than 0.5%. Morishita et al., in Novel Oral Insulin Delivery Systems Based
on Complexation Polymer Hydrogels, J. Controlled Release 110 (2006)
587-594 also states that polymeric carriers, lipid-based carriers such as
liposomes and solid lipid nanoparticles show low bioavailability as
insulin delivery agents. In a press release in Pharmaceutical News dated
Jun. 2, 2004, BioSante Pharmaceuticals, Inc. announced what it said were
positive results of a preclinical study of a calcium phosphate
nanoparticle (CAP) delivery system or oral delivery of insulin. Barclay,
Md., in a Jan. 31, 2003 press release by Medscape Medical News, entitled
Oral Insulin Effective in Type 2 Diabetes, reported the use of an oral
insulin formulation, oral hexyl-insulin monoconjugate 2. Hagan et al. in
an abstract entitled Polylactide-Poly(ethylene glycol) Copolymers as Drug
Delivery Systems. 1. Characterization of Water Dispersible
Micelle-Forming Systems, Langmuir, 12 (9), 2153-2161 (1996) discusses
copolymers of polylactide and PEG which are said to self disperse in
water to form spherical nonionic micelles as a drug delivery system.
Finally, U.S. Pat. No. 7,153,520 to Seo et al. purports to disclose an
implant for injection into the body which is associated with a
composition for sustained delivery of a drug comprising an amphiphilic
diblock copolymer; a poorly water-soluble drug; a biodegradable polymer;
and liquid poly(ethylene glycol) (PEG).

[0006]Each of the foregoing patents, publications, applications and
references is incorporated herein by reference as if fully set forth
herein.

SUMMARY OF THE INVENTION

[0007]In general, the present application relates to "nanocapsules," which
term refers to a number of nanoparticles, including, but not limited to,
nanovesicles, micelles, lamellae shaped particles, polymersomes,
dendrimers, and nano-size particles of various other small fabrications
that are known to those in the art. The nanocapsules falling within the
general scope of the present invention are drug delivery vehicles that
deliver drugs, particularly, peptides and proteins such as insulin, to
the gastrointestinal portions of the body where they are absorbed without
appreciable degradation by resident enzymes. More particularly, in one
aspect of the invention, the nanocapsules are comprised of amphiphilic
diblock amino acid or amino acid derivative polymers. In a general aspect
of the invention, when these diblocks are in solution, such as the
environment of the stomach and intestines, the nanocapsules form and
adhere to, or partially adhere to, absorb or encapsulate, the drug
molecules of interest, including those that heretofore have not been
successfully formulated for oral drug delivery, such as polypeptides and
macromolecules, e.g., insulin. Nanocapsule full or partial absorption or
encapsulation of such drug molecules enables their delivery via oral or
mucosal means including by the inclusion of the diblock formulation in
tablet, capsule, caplet, powder, liquid, suspension and other
pharmaceutical forms known to those of skill in the art of the drug and
pharmaceutical industries.

[0008]While other copolymers fall within scope of the present invention,
one general aspect of the present application is directed to diblock
copolymers, and certain single polymers. For example, conventional
thinking is that a triblock polymer is important to form a proper wall
for a nanoparticulate drug carrier. However, the applicants herein have
discovered that a diblock polymer form is a particularly effective
nanoparticulate drug carrier.

[0009]Thus, in general, the present invention pertains to molecules with a
particular mechanism of action. The linear amphiphilic molecules herein
described comprise a diblock polymer ("A-B Polymer") with the A chain
being at least partially hydrophobic and the B chain being at least
partially hydrophilic. Further, in one aspect of the present invention,
the A and B copolymer units comprise amino acids or derivatized amino
acids.

[0010]In summary fashion, the diblock polymers comprising one aspect of
the present invention can be described as follows:

[0011]A diblock polymer comprising polymer blocks A and B, wherein
[0012]A is at least a partially hydrophobic block and [0013]B is at least
a partially hydrophilic block, and

[0014]wherein A and B further comprise amino acids or derivatized amino
acids.

[0015]When put into a hydrophilic environment e.g., an aqueous solution,
the polymer will spontaneously form nanocapsules, e.g, micelles and/or
lamellae shaped particles, with the lipophilic end facing inward to
`hide` from the water. The nanocapsule assembly can resemble a particle,
since the individual lipophilic ends are attracted with a force called
Van der Waals attraction. Additionally, the process of nanocapsule (e.g.,
micelle) formation is sometimes called hydrophobic bonding.

[0016]Thus, one object of the present invention is to provide molecules
that are designed to deliver drugs by routes difficult to pursue by other
means, such as oral delivery of sensitive drug molecules such as insulin
and other peptides or polypeptides.

[0017]Another object of the invention is to provide nanocapsules that at
least partially adhere to, absorb and/or encapsulate drug molecules in
the body.

[0018]Another object of the invention is to provide a delivery vehicle for
drugs to be absorbed into the stomach, intestines and/or gastrointestinal
tract without degradation of such drugs, e.g., insulin, by enzymes
resident in those areas of the body.

[0019]Another object of the invention is to provide a new oral or mucosal
delivery means for drug molecules in general.

[0020]Another object of the invention of the present invention is to
provide a delivery system, such as a tablet, capsule, liquid, suspension,
intravenous, intraperitoneal, subcutaneous, intrathecal, and opththalmic
means for the delivery or administration to a patient of insulin and
other polypeptides and proteins.

[0021]Another object of the invention is to provide a diblock polymer that
forms nanocapsules when the polymer is introduced into aqueous media.

[0022]Another object of the invention is to provide nanocapsules that are
capable of at least partially absorbing, encapsulating or adhering to
drug molecules and serving as drug carriers.

[0023]Additional advantages, uses and features of the aspects of the
invention described herein will be apparent to those of skill in the art
from the detailed description which follows, including the accompanying
example and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024]FIG. 1 is a graphical representation of the results of a study
measuring inter alia the concentration over time of glucose and insulin
in an insulin formulation of the present invention wherein said insulin
formulation was administered orally to an animal.

[0025]FIG. 2 is a graphical representation of the results of a study
measuring inter alia concentration over time of insulin and glucose
levels wherein insulin was not formulated in accordance with the present
invention and wherein the insulin was administered orally to an animal.

DETAILED DESCRIPTION OF THE INVENTION

[0026]Numerous technologies and entities are commonly embraced by the
catch all terms "nanotechnology" and "nanoparticles." A "nanoparticle" is
a term that relates to a number of entities, many of which are known to
one of skill in the art and which are incorporated herein by reference.
One thing in common, however, is that nanoparticles or "nanostructures"
are usually sufficiently small to be measured in nanometers.

[0027]A term used in this application, "nanocapsule" refers to a number of
nanoparticles, including, but not limited to, nanovesicles, micelles,
lamellae shaped particles, polymersomes, dendrimers, and other nano-size
particles of various other small fabrications that are known to those in
the art. The definitions and understandings of the entities falling
within the scope of nanocapsule are known to those of skill in the art,
and such definitions are incorporated herein by reference and for the
purposes of understanding the general nature of the subject matter of the
present application. However, the following discussion is useful as a
further understanding of some of these terms.

[0028]For example, a "micelle", a useful article in the employment of a
general aspect of the present invention, can generally be thought of as a
small--on the order of usually nanometers in diameter--aggregate of
amphiphilic linear molecules having a polar, or hydrophilic end and an
opposite non-polar, or hydrophobic end. These linear molecules can be
comprised of simple molecules, or polymeric chains. A micelle can also be
referred to as an aggregate of surfactant molecules dispersed in a liquid
colloid. A typical micelle in aqueous solution can form an aggregate with
the hydrophilic "head" regions in contact with surrounding solvent, and
the sequestering of the hydrophobic tail regions in the micelle center.
Other and similar definitions, descriptions and understandings of
micelles are also known to those of skill in the art and are incorporated
herein by reference.

[0029]Polymersomes" can, in general, be thought of as bilayered membranes
of amphiphilic synthetic polymers, which are similar in some respects to
liposomes, which use naturally occurring lipids. While having some of the
properties of natural liposomes, polymersomes exhibit increased stability
and reduced permeability. Other and similar definitions, descriptions and
understandings and of polymersomes are also known to those of skill in
the art and are incorporated herein by reference.

[0030]Dendrimers" have descriptions, definitions and understandings in the
literature. For example, and without limitation and including other and
similar definitions, descriptions and understandings in the art, the term
dendrimer from the Greek word, "dendron", for tree, can refer to a
synthetic, three-dimensional molecule with branching parts. Descriptions
and understandings of dendrimers can be gleaned from Holister et al.,
DENDRIMERS, Technology White Papers nr. 6, pub. October 2003 by
cientifica, as well as the other literature published by those skilled in
the art on dendrimers, all of which are incorporated herein by reference.

[0031]Lamella" is a term whose definitions, descriptions and
understandings are also known to those of skill in the art and which are
incorporated herein by reference. In a very general sense, lamella or
lamellae refers to plate-like, gill-shaped or other layered structures.

[0032]The definitions, descriptions and understandings of "nano-vesicle"
are well known to those of skill in the art, and are incorporated herein
by reference. For example, "nanovesicle" can refer to a variety of small
sac, sac-like or globular structures capable of containing fluid or other
material therein.

[0033]Generally speaking, the present invention relates to drug delivery
formulations that utilize nanocapsules to deliver drugs, particularly,
peptides and proteins such as insulin, to the gastrointestinal portions
of the body where they are absorbed without appreciable degradation by
resident enzymes. The nanocapsules are generally comprised of block and
diblock polymers and are formed in solution or suspension where they can
be combined with the drug molecule of interest. In a general aspect of
the invention, the diblock polymers are comprised of amphiphilic amino
acid, or amino acid derivative, copolymers. When these diblocks are in
solution or suspension, nanocapsules form and can adhere to, or partially
adhere to, and can at least partially absorb or encapsulate, drug
molecules, including, but not limited to, those that heretofore have not
been successfully formulated for oral drug delivery, such as polypeptides
and macromolecules, e.g., insulin, insulin derivatives and analogues,
growth hormones and analogues thereof, eyrthropoeitins, anti-inflammatory
peptides, anti-aging peptides, atrial natriurectic peptides, brain injury
derived peptides, Calcitonin, defensins, deltorphins, dermorphins and
analogues thereof, BAM peptides, α-casein exorphins, dynorphins,
endomorphins, endorphins, enkephalins, gluten exorphins, kyotorphins,
methorphamide, neoendorphins, syndyphalins, valorphin, dynorphin and
analogues and sequences thereof, enterostatins, Ghrelins, glucagons and
glucagon-like peptides such as GLP-1 and GLP-2, gonadotropin releasing
hormones, growth hormone releasing hormones, insulino-tropic compounds,
kyotorphins, leptin and fragments thereof, secretins, thymosins and
fragments thereof, transforming growth factors and fragments thereof,
tuftsin, tumor necrosis factors and related peptides, and VIP, Prepro
VIP, and analogs and fragments thereof. A nanocapsule falling within the
scope of the present invention effects full or partial adherence,
absorption or encapsulation of such drug molecules and thereby enables
their delivery via oral or mucosal means. One aspect of the present
invention also employs a single polymer such as is exemplified in some of
the alternative embodiments described below.

[0034]Thus, one aspect of the present invention is a type of copolymer
called a "block copolymer", a term whose definitions and understandings
are well known in the art and which are incorporated by reference herein.
In a general sense, block copolymers are comprised of two or more polymer
subunits linked by covalent bonds. Block copolymers with two or three
distinct blocks are called diblock copolymers and triblock copolymers,
respectively. Copolymers may also be described in terms of the existence
of or arrangement of branches in the polymer structure. Linear copolymers
consist of a single main chain whereas branched copolymers consist of a
single main chain with one or more polymeric side chains. Block
copolymers are made up of blocks of different polymerized monomers.
Triblocks, tetrablocks, multiblocks can be made. Block copolymers are of
interest because they can "microphase separate" to form periodic
nanostructures.

[0035]While other copolymers fall within scope of the invention, one
aspect of the present application is directed to diblock copolymers,
although single chain and other polymers may be used. As mentioned above,
conventional thinking is that a triblock polymer is important to form a
proper wall for a nanoparticulate drug carrier. However, the applicants
herein have found that the diblock polymer form, and in some cases the
single polymer form, is a particularly advantageous and effective
nanoparticulate drug carrier. According to one general aspect of the
present invention, the evidence strongly suggests that the diblock
polymers of the present invention form nanocapsules such as those with a
lamella-like configuration, alone or together with nanocapsules of
micelle configuration. The lipid block of the nanocapsule (e.g.,
n-butyl-poly-l-lactide) intercalates or interweaves in aqueous solution
and the polar group of the nanocapsule (e.g., polyglutamic acid with
associated drug, e.g., insulin) faces the aqueous solution both inside
and out when the nanocapsules are formed. The nanocapsule assembly
resembles a particle, since the individual lipophilic ends are attracted
with a force called Van der Waals attraction. The process of nanocapsule
formation is sometimes called hydrophobic bonding. In accordance with the
aforementioned mechanism of action, when the nanocapsule/drug is in the
physiological media of the gastrointestinal tract, the drug that has been
formulated with it is protected by the nanocapsule so it may be absorbed
intact by the tissues of the body and introduced into the blood stream
before it can be degraded by gastrointestinal enzymes. Experimental
support for this mechanism is set forth in the example below wherein
effective oral delivery of insulin utilizing this aspect of the invention
is demonstrated.

[0036]Hagan and Seo et al., referred to above, concerns, inter alia,
PEG-PLA diblock polymers. Although they are diblock polymers, they differ
from the poly(lactic acid)-poly(glutamic acid) diblock aspect of the
present invention which uses poly(glutamic acid) as the hydrophilic
block, instead of polyethylene glycol, PEG. PEG-PLA diblock polymers can
only deliver hydrophobic drugs, if at all. One aspect of the present
invention is that it can deliver hydrophilic polypeptides and proteins,
e.g. insulin. Further, PEG has no charges on the polymer backbone, while
poly(glutamic acid), as used within the scope of the present invention,
has negative charges at neutral and basic pH, and thus can absorb or
encapsulate hydrophilic proteins for drug delivery.

[0037]Also, both blocks of the diblock polymers included within the
present invention are biodegradable. In addition, the diblock polymer
nanocapsule structures encapsulate aqueous solutions with hydrophilic
proteins inside the nanocapsule. As mentioned above, the poly(glutamic
acid) on the outer surface of the nanocapsule adsorbs hydrophilic
proteins. The PEG-PLA block polymers of the prior art are not known to
form nanocapsules. Rather they form a hydrophobic PLA hard core with PEG
sticking out into the aqueous phase of a solution. Further, PEG does not
absorb proteins, and thus a PEG-PLA drug delivery agent mainly depends on
the encapsulation of hydrophobic drugs in the PLA core, not the PEG.

[0038]In general, the present invention pertains to amphiphilic molecules
comprising a diblock ("A-B Polymer") with the A chain being at least
partially hydrophobic and the B chain being at least partially
hydrophilic. Further, in one aspect of the present invention, the A and B
copolymers comprise amino acids or derivatized amino acids. Still
further, in another aspect of the invention, the B polymer alone is
sufficient to provide the nanocapsule drug delivery agent. In summary
fashion, the diblock polymers comprising one aspect of the present
invention can be summarized as follows:

[0039]A diblock polymer comprising polymer blocks A and B, wherein
[0040]A is at least a partially hydrophobic block and [0041]B is at least
a partially hydrophilic block, and

[0042]wherein A and B further comprise amino acids or derivatized amino
acids.

[0043]The nature of the amphiphilic diblock amino acid (or derivatized
amino acid) polymer of the present invention is such that when it is in
suspension or solution it will spontaneously form nanocapsules, with a
lipophilic end facing inward to `hide` from water, which at least
partially, encapsulate, absorb, partially or fully, or adhere to, the
drug molecule of interest added to the nanocapsules. Thus, as aforesaid,
when the nanocapsules are in the aqueous media of the stomach, intestines
and gastrointestinal tract, they are absorbed by the tissues and the
drug, e.g., a polypeptide or protein, is delivered safely and without
appreciable degradation by the body's enzymes.

[0044]The type of molecules of the present invention are generally
designed and are useful to deliver drugs by routes difficult to pursue by
other means, such as oral delivery of sensitive drug molecules such as
insulin and other peptides or polypeptides. However, other small
conventional drug molecules are included within the present invention,
and the success depends upon the ionic nature of the compounds, and
whether they will form complexes with the diblocks. Since the
nanocapsules formed by the copolymers of this invention adhere to, absorb
and/or encapsulate the drug molecule, the drug may be delivered orally or
through mucosal membranes. Further, since the nanocapsules formed as
described herein are capable of absorbing, encapsulating or adhering to a
drug, they are highly useful as drug carriers. Because of their size and
sensitive drug carrier capabilities, the nanocapsules of the present
invention provide unique and precise drug carrier capabilities. Thus, one
advantage of the present invention is that polypeptide and protein drugs,
e.g., insulin, and other macromolecules may be delivered orally, or
through other mucosal membranes, whereas other technologies have failed
or had severe shortcomings. In addition, other delivery routes falling
within the scope of the present invention include intravenous,
intraperitoneal, subcutaneous, intrathecal, opththalmic, intranasal,
liquid, inhaler and other delivery routes known in the art.

[0045]A description of one embodiment of the A-B block copolymer of the
present invention is as follows:

TABLE-US-00001
Exemplary Amount
Composition (% w/w) General Composition
Block A: 50 Block A is a lipophilic polymer
n-butyl-poly-1-lactide approximately 100 units or as
determined suitable for delivery of
insulin or other peptides by the oral
route.
Block B: 50 Block B is a hydrophilic amino acid
poly-1-glutamic acid polymer, approximately 100 units
or as determined suitable for
delivery of insulin or other peptide

[0046]These A-B polymer compositions are easily made using standard wet
chemical methods. The major step, the coupling of A and B, is usually
accomplished under anhydrous conditions using standard peptide
dehydrative coupling reactions, such as is achieved with
dicyclohexylcarbodiimide. Other coupling reagents are known to
practitioners skilled in the art as being useful for coupling, and
include polymer fusion reagents and peptide coupling reagents that can
carry out the joining of the two polymeric blocks. Diblock copolymers can
also be made using living polymerization techniques, such as atom
transfer free radical polymerization (ATRP), reversible addition
fragmentation chain transfer (RAFT), ring-opening metathesis
polymerization (ROMP), and living cationic or living anionic
polymerizations.

EXAMPLE

Synthesis of Diblock Copolymer

[0047]The amphiphilic diblock copolymer, poly(lactic acid)-poly(glutamic
acid), was made by living polymerization of individual poly(lactic acid)
and poly(glutamic acid) blocks, then coupling the two blocks together. In
the diblock polymer used in the following pig study, each poly(lactic
acid) block has approximately 150 lactic acid repeating units, and each
poly(glutamic acid) block has approximately 100 glutamic acid repeating
units, which were confirmed by Gel Permeation Chromatography ("GPC") and
Multi-Angle Laser Light Scattering ("MALLS").

[0048]After the coupling reaction, the diblock polymer was precipitated
and washed in water. 30 mL of aqueous polymer suspension with about 3%
polymer content was sonicated for 15 minutes, then 10 mL of 1% insulin
solution was added. The final pH was 7.4. In the final formulation, there
were 2.2% diblock nanocapsule and 0.25% insulin at pH 7.4 ("Formulation
A"). The insulin was added after the diblock nanocapsules were formed, so
insulin was adsorbed on the outside of the nanocapsules, or freely
floating in the aqueous phase.

Yucatan Minipig Study

[0049]Yucatan pigs were prepared for the study with the surgical
implantation of a jugular catheter for easy blood collection. Baseline
venous blood specimens were collected just prior to the dosing treatment
and blood was thereafter sampled at 0 (just before treatment), 30, 60,
90, 120, 150 and 240 minutes after treatment. Each pig was monitored with
a hand-held commercial glucometer (Lifescan, J&J; One Touch Fast
Take®) at each blood collection time to ensure animal wellness, and to
give an immediate indication of any biological activity as is verified by
glucose reduction compared to the baseline levels.

[0050]The blood was collected into sodium heparinized plastic tubes. The
plasma was retrieved and stored at -20° C. until analyzed for
insulin and glucose.

[0052]The pigs were dosed with either insulin solution at 0.25% (Control)
or nanocapsule associated insulin at 0.25% (Formulation A). Each
formulation was dosed by oral gavage, 4 mL of formulation, followed by 4
ml of saline wash to rinse the tubing.

Results and Discussion

[0053]After administering 4 mL of diblock (Formulation A) orally, the pigs
showed glucose reduction at about 30 minutes. See Table 1 and FIG. 1.
This pharmacodynamic result was confirmed by the pharmacokinetic blood
insulin concentration increase. The insulin assay measured both the
endogenous pig insulin and human insulin. Table 1 and FIG. 1 show the
performance of oral 4 mL 0.25% insulin (Formulation A) with 2.2%
poly(lactic acid)-poly (glutamic acid) nanocapsules at pH 7.4. Glucose
levels were also measured and obtained. A graphical representation of
these data is shown in FIG. 1.

[0054]The result of administration of 4 mL of 0.25% insulin solution
(without nanocapsules) orally to the pigs as a control is illustrated in
Table 2 and FIG. 2. The results of the control experiment are in accord
with the well known fact that insulin without protection can not survive
the stomach and intestine, which is the reason why, to the inventors
knowledge, insulin has not yet been taken orally in an effective manner.
The insulin and glucose results for this control (see Table 2 and FIG. 2)
confirmed that the pig glucose was unchanged; it also showed the baseline
insulin level in the pigs. FIG. 2 also graphically shows the performance
of oral 4 mL 0.25% insulin solution at pH 7.4.

[0055]In sum, Table 2 shows the experimental results of oral 4 mL 0.25%
insulin solution at pH 7.4. Glucose levels were also measured and
obtained. A graphical representation of these data are shown in FIG. 2.

[0056]The experimental results confirm that a poly(lactic
acid)-poly(glutamic acid) nanocapsule can protect insulin at least
partially absorbed on or in the nanocapsule upon transit through the
stomach and the intestine, and deliver insulin to the blood stream, even
without the use of enteric coating on the formulation. The interaction
between the insulin molecule and the poly(glutamic acid) on the outer
surface of the nanocapsule is one key factor. The poly(glutamic acid)
acts as a coating protecting the insulin. The inventors have deduced that
in the acidic environment in the stomach, poly(glutamic acid) is
protonated, becomes hydrophobic and protects the adsorbed insulin inside.
In the intestine, protonated poly(glutamic acid) lost protons due to the
higher pH and stretched out due to charge repulsion, then released the
insulin. The poly(lactic acid) block functioned to aggregate the
molecules into nanocapsules of uniformly small particle size that enabled
them to be uptaken by an as yet unknown mechanism through the intestinal
mucosal cells.

[0057]As the results of these experiments show, the present invention is a
breakthrough discovery in the field of oral insulin delivery and is a new
way of delivering insulin orally. As shown by the data presented above
and the graphical representations in FIGS. 1 and 2, the polymeric
nanocapsule formulations of the present invention show superior results
in the drug delivery of insulin.

[0058]The following are further examples of selected embodiments of the
invention in addition to that described above. They are not meant to be
limiting of the scope of the invention and other embodiments will be
apparent to those skilled in the art.

[0059]A second embodiment of the invention comprises a composition
comprising a diblock polymer having components A and B, wherein A can be
at least a partially hydrophobic block, B can be at least a partially
hydrophilic block, and wherein said composition may form one or more of
the following entities, for example, in solution or suspension:
nanovesicles, micelles, lamellae particles, polymersomes, dendrimers, and
other nano-size particles of various fabrications, including, but not
limited to, those that are known to those of skill in the art.

[0060]A third embodiment of the invention comprises the composition of the
second embodiment wherein a drug may be at least partially absorbed or
encapsulated by, or adhered to, one or more of the following entities:
nanovesicles, micelles, lamellae particles, polymersomes, dendrimers, and
other nano-size particles of various fabrications, including, but not
limited to, those that are known to those of skill in the art.

[0061]A fourth embodiment of the invention comprises the composition of
the second embodiment wherein a drug may be at least partially absorbed
or encapsulated by, or adhered to, nanocapsules.

[0062]A fifth embodiment of the invention comprises the composition of the
second embodiment wherein the A block may be, for example, a polylactide,
polycaprolactide, or polyglycolide composition, of either enantiomeric,
racemic, or other isomeric forms such as meso.

[0063]A sixth embodiment of the invention comprises the composition of the
second embodiment wherein the B block may be, for example, polyamino
acids with ionic nature, of either enantiomeric, racemic, or other
isomeric forms such as meso.

[0064]A seventh embodiment of the invention comprises the composition of
the second embodiment wherein the B block may be polyaminoacids with
anionic nature, for example, polyglutamic and polyaspartic amino acids,
or copolymers of the two.

[0065]An eighth embodiment of the invention comprises the composition of
the second embodiment wherein the B block may be polyaminoacids with
cationic nature, for example, polylysine, polyarginine, polyhistidine, or
copolymers of the three taken two or three at a time.

[0066]A ninth embodiment of the invention comprises the composition of the
third embodiment of the invention wherein the drug is a polypeptide or
macromolecule.

[0067]A tenth embodiment of the invention comprises the composition of the
third embodiment of the invention wherein the drug is a polypeptide or
macromolecule.

[0068]An eleventh embodiment of the invention comprises the composition of
the third embodiment of the invention wherein the drug may be insulin or
derivative or analog of insulin.

[0069]A twelfth embodiment of the invention comprises the composition of
the third embodiment of the invention which differs, however, in that
instead of having A and B block copolymers, the composition may comprise
only the B block as a polyamino acid capable of complexing with the drug
in such a way as to protect the drug before being uptaken by the
intestine after oral delivery.

[0070]A thirteenth embodiment of the invention comprises the composition
of the sixth embodiment of the invention which differs, however, in that
instead of having A and B block copolymers, the composition may comprise
only the B block as disclosed in embodiments 6 through 8.

[0071]A fourteenth embodiment of the invention comprises the composition
of the seventh embodiment of the invention which differs, however, in
that instead of having A and B block copolymers, the composition may
comprise only the B block as disclosed in embodiments 6 through 8.

[0072]A fifteenth embodiment of the invention comprises the composition of
the eighth embodiment of the invention which differs, however, in that
instead of having A and B block copolymers, the composition may comprise
only the B block as disclosed in embodiments 6 through 8.

[0073]Further embodiments of the invention comprise the composition of the
second through fifteenth embodiments of the invention wherein one or more
of the blocks may vary in length between approximately 10 and 500
monomeric units, preferably between approximately 25 and 200 units, and
most preferably between approximately 50 and 150 units.

[0074]This application and the various aspects of the invention herein are
not limited to the embodiments illustrated above, and other embodiments
will be apparent to those of skill in the art. The embodiments described
above are meant to be illustrative and not limiting.